Metal organic compounds

ABSTRACT

The invention relates to the synthesis and provision of a new class of volatile metal organic compounds based on bis(alkylimine)glyoxal and bis(dialkylhydrazone)glyoxal ligands in combination with cyclopentadienide and alkyl ligands for use in ALD and CVD processes.

The invention relates to the synthesis and provision of a new class of volatile and liquid ruthenium compounds that is not yet mentioned or used in the literature and is based on bis(alkylimine)glyoxal and bis(dialkylhydrazone)glyoxal ligands in combination with cyclopentadienide and alkyl ligands, for use in ALD and CVD processes.

The objective of the invention is the provision of an innovative class of ruthenium compounds that are liquid and volatile at or slightly above room temperature, for use in atomic layer deposition (ALD) or/and chemical vapor deposition (CVD) processes.

This objective is achieved by a class of compounds of the general formula

that can also be represented by the general formula [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³], which is used in this description as well. The cyclopentadienyl groups of the form (CpR²¹R²²R²³R²⁴R²⁵) can usually form η⁵- and η³-complexes with the ruthenium.

R²¹, R²², R²³, R²⁴ and R²⁵ are, independently from each other, selected from the group consisting of H, C1-C6 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl and NR³¹ ₂, wherein R³¹ is selected from the group consisting of H, C1-C6 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl and C3-C6 aryl;

or R²¹, R²², R²³, R²⁴ and R²⁵ are, independently from each other, selected from the group consisting of H, C1-C3 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl and NR³¹ ₂, wherein R³¹ is selected from the group consisting of H, methyl, ethyl, isopropyl; or

R²¹, R²², R²³, R²⁴ and R²⁵ are, independently from each other, selected from the group consisting of H, C1-C3 linear alkyl or C3-C6 branched alkyl, in particular R²¹, R²², R²³, R²⁴ and R²⁵ are, independently from each other, selected from the group consisting of H, methyl, ethyl, isopropyl and tert.-butyl. In another specific embodiment, R²¹ to R²⁵ are not identical, but at least one of R²¹ to R²⁵ is different;

or two of R²¹, R²², R²³, R²⁴ and R²⁵ are interconnected by a C3 to C6 alkyl, alkenyl, alkadienyl or alkatrienyl forming an annelated ring that can be substituted or unsubstituted. In a specific embodiment of the invention, two of R²¹, R²², R²³, R²⁴ and R²⁵ are so linked to each other as to form an annelated phenylene which can be substituted or unsubstituted, in sum resulting in (CpR²¹R²²R²³R²⁴R²⁵) being an indenyl ligand, which can be substituted or unsubstituted.

(R⁴R⁵(DAD)R⁶R⁷) represents a chelating 1,4-diazadiene or its bis-hydrazone derivative of the general formula (R⁴)—N═CR⁵—CR⁶═N—(R⁷) wherein R⁴ and R⁷ can be independently selected from the group consisting of C1-C6 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl; or R⁴ and R⁷ can be independently selected from the group consisting of C1-C3 linear alkyl, C3-C5 branched alkyl and C3-C6 cyclic alkyl; or R⁴ and R⁷ are, independently from each other, selected from the group consisting of C1-C3 linear alkyl or C3-C5 branched alkyl, in particular R⁴ and R⁷ are, independently from each other, selected from the group consisting of methyl, ethyl, isopropyl and tert.-butyl.

R⁵ and R⁶ can be independently selected from the group consisting of H, C1-C6 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl; or R⁵ and R⁶ can be independently selected from the group consisting of H, C1-C3 linear alkyl, C3-C5 branched alkyl and C3-C6 cyclic alkyl; or R⁵ and R⁶ are, independently from each other, selected from the group consisting of H, C1-C3 linear alkyl or C3-C5 branched alkyl, in particular R⁵ and R⁶ are, independently from each other, selected from the group consisting of H, methyl, ethyl, isopropyl and tert.-butyl.

In another specific embodiment, R⁵ and R⁶ can be independently selected from the group consisting of H, C1-C3 linear alkyl, C3-C5 branched alkyl and C3-C6 cyclic alkyl, more specifically selected from the group consisting of H, C1-C3 linear alkyl or C3-C5 branched alkyl, in particular selected from the group consisting of H, methyl, ethyl, isopropyl and tert.-butyl and

R⁴ and R⁷ are selected from the group consisting of C1-C3 linear alkyl, C3-C5 branched alkyl and C3-C6 cyclic alkyl, more specifically selected from the group consisting of C1-C3 linear alkyl or C3-C5 branched alkyl, in particular selected from the group consisting of methyl, ethyl, isopropyl and tert.-butyl.

In another specific embodiment, R⁴ to R⁷ are not identical, but at least one of R⁴ to R⁷ is different; more specifically, R⁴ to R⁷ are different from each other.

In another specific embodiment, R⁴ and R⁷ can, independently of each other, also be (R⁸,R⁹)N— and (R¹²,R¹³)N—, respectively, i.e. R⁴ can be (R⁸,R⁹)N— and/or R⁷ can be (R¹²,R¹³)N—. Consequently, in these cases (R⁴R⁵(DAD)R⁶R⁷) can be selected from the group consisting of (R⁸,R⁹)N—N═CR⁵—CR⁶═N—N(R¹²,R¹³), R⁴—N═CR⁵—CR⁶═N—N(R¹²,R¹³), (R⁸,R⁹)N—N═CR⁵—CR⁶═N—R⁷, R⁴—N═CR⁵—CR⁶═N—R⁷ and combinations thereof.

R⁸, R⁹, R¹² and R¹³ can be independently selected from the group consisting of H, C1-C6 linear alkyl, C3-C6 branched alkyl, or two neighbouring groups, such as R⁸ and R⁹ or R¹² and R¹³, can together form a C3-C6 saturated or unsaturated cyclic alkyl, which may contain a heteroatom selected from O or S. More specifically, R⁸, R⁹, R¹² and R¹³ can be independently selected from the group consisting of H, C1-C3 linear alkyl, C3-C5 branched alkyl and two neighbouring groups, such as R⁸ and R⁹ or R¹² and R¹³ together forming a saturated C3-C6 cyclic alkyl, which may contain a heteroatom; or R⁸, R⁹, R¹² and R¹³ can be, independently from each other, selected from the group consisting of C1-C3 linear alkyl, C3-C5 branched alkyl or two neighbouring groups, such as R⁸ and R⁹ or R¹² and R¹³ together forming a C4 to C6 saturated cyclic alkyl, which may contain a heteroatom selected from O or S; in particular R⁸, R⁹, R¹² and R¹³ can be, independently from each other, selected from the group consisting of methyl, ethyl, isopropyl, tert.-butyl, pyrrolidinyl, piperidinyl or morpholinyl.

In another specific embodiment, if either R⁴ is (R⁸,R⁹)N— or R⁷ is (R¹²,R¹³)N—, then the respective other one is not, thus resulting in (R⁴R⁵(DAD)R⁶R⁷) being selected from the group consisting of R⁴—N═CR⁵—CR⁶═N—N(R¹²,R¹³) with R⁴ being different from (R⁸,R⁹)N, (R⁸,R⁹)N—N═CR⁵—CR⁶═N—R⁷ with R⁷ being different from (R¹²,R¹³)N and combinations thereof.

R³ can be selected from the group consisting of H, C1-C6 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl, C3-C6 vinyl, C3-C6 allyl, C3-C6 alkenyl; or, R³ may be H, C1-C3 linear alkyl or C3-C5 branched alkyl, in particular R³ may be selected from the group consisting of H, methyl, ethyl.

Yet another embodiment can be represented by the formula

In this embodiment, R³ to R⁷ as well as R²³ to R²⁵ are defined as above, or R²³ to R²⁵ can be, independently of each other, hydrogen, methyl or ethyl, or if one of R²³ to R²⁵ is methyl or ethyl, then the other two are hydrogen; or, if R²⁴ is ethyl or methyl, in particular methyl, then R²³ and R²⁵ are hydrogen.

Within the scope of the present patent application, C1-C6 alkyl means methyl (C1), ethyl (C2), propyl (C3), butyl (C4), pentyl (C5) and hexyl (C6). Propyl covers both n-propyl and iso-propyl. Butyl covers n-butyl, iso-butyl, sec-butyl and tert-butyl. Pentyl covers n-pentyl (amyl), 2-pentyl (sec-pentyl), 3-pentyl, 2-methylbutyl, 3-methylbutyl (iso-pentyl or iso-amyl), 3-methylbut-2-yl, 2-methylbut-2-yl and 2,2-dimethylpropyl (neo-pentyl). The term hexyl likewise covers all possible isomers.

According to the present invention, an innovative, volatile ruthenium compound class that is liquid at room temperature and allows for purification by distillation or recondensation is provided. The compound class of the present invention having the formula [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³] can deposit ruthenium containing layers (elemental ruthenium layers or with a suitable co-reagent mixed ruthenium containing layers, eg. RuO) on a surface by means of a thermally-induced decomposition. As a result of the range of variation of the substitution pattern of the Cp and (R⁴R⁵(DAD)R⁶R⁷) ligands, volatility and thermal degradation can be adapted to the application in various ALD and CVD processes.

In this respect, the given ligands (CpR²¹R²²R²³R²⁴R²⁵) refer to all cyclopentadienide ligands in unsubstituted form as well as with substituents R²¹ to R²⁵ as defined above.

For example, Cp is an unsubstituted cyclopentadienide ligand (wherein in the formula (CpR²¹R²²R²³R²⁴R²⁵) all substituents R²¹ to R²⁵ are hydrogen) and CpCH₃ or CpMe is a monomethyl substituted cyclopentadienide ligand, Cp* is a pentamethyl substituted cyclopentadienide ligand and may be written in short C₅Me₅ and EtCp is a monoethyl substituted cyclopentadienide ligand with the abbreviation C₅H₄Et. These belong to the most common cyclopentadienide ligands.

The given ligands (R⁴R⁵(DAD)R⁶R⁷) refer to compounds of the classes of bis(alkylimine)glyoxals with the general formula (R⁴)—N═CR⁵—CR⁶═N—(R⁷) or bis(dialkylhydrazone)glyoxals with the general formula (R⁸,R⁹)NN═CR⁵—CR⁶═N—N(R¹²,R¹³), wherein R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹² and R¹³ are as defined above.

By reaction of [((CpR²¹R²²R²³R²⁴R²⁵))Ru(PPh₃)₂Cl] or [((CpR²¹R²²R²³R²⁴R²⁵))RuCl]₄ with R⁴R⁵(DAD)R⁶R⁷, [((CpR²¹R²²R²³R²⁴R²⁵))Ru(R⁴R⁵(DAD)R⁶R⁷)Cl] precursors can be produced at high yields of usually 60% or higher. By a simple reaction of these precursors with appropriate Grignard compounds of the formula R³MgX, wherein X is selected from the group consisting of F, Cl, Br and I, or with lithium alkyl compounds of the formula R³Li, the precursor can be converted into the respective alkyl complex [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³].

It is advantageous to employ [(CpR²¹R²²R²³R²⁴R²⁵)Ru(PPh₃)₂Cl] as the starting compound. It is also possible that instead of triphenyl phosphine, PPh₃ as mentioned above, other suitable phosphines can be used, which encompass, for example, tricyclohexylphosphine PCy₃, tri-ortho-tolylphosphine and related compounds.

In general, phosphines of the type P(R³⁸)₃ with R³⁸ being selected from the group consisting of substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkyloxy, substituted or unsubstituted C1-C6 alkenyl, substituted or unsubstituted C1-C6 alkinyl, substituted or unsubstituted C1-C6 alkadienyl, substituted or unsubstituted C3-C6 cycloalkyl, substituted or unsubstituted C5-C10 aryl, substituted or unsubstituted C5-C10 aryloxy and combinations thereof, in particular substituted with one, two or three substituents selected from the group consisting of ethyl, methyl, propyl, isopropyl, butyl, tert.-butyl, and combinations thereof, and wherein R³⁸ can specifically be ethyl, methyl, propyl, isopropyl, butyl, tert.-butyl, cyclohexyl, phenyl, tri-ortho-tolyl, tri-meta-tolyl, tri-para-tolyl, methoxy, ethoxy, phenyloxy and combinations thereof.

Also phosphines of the general formula (R³⁹)P—R⁴⁰ ₂ or (R³⁹)₂P—R⁴⁰, with R³⁹ being selected from the group consisting of substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkyloxy, substituted or unsubstituted C1-C6 alkenyl, substituted or unsubstituted C1-C6 alkinyl, substituted or unsubstituted C1-C6 alkadienyl, substituted or unsubstituted C3-C6 cycloalkyl, substituted or unsubstituted C5-C10 aryl, substituted or unsubstituted C5-C10 aryloxy and combinations thereof, in particular substituted with one, two or three substituents selected from the group consisting of ethyl, methyl, propyl, isopropyl, butyl, tert.-butyl, and combinations thereof; and

R⁴⁰ being different from R³⁹ and selected from the group consisting of substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C5-C10 alkyloxy, substituted or unsubstituted C1-C6 alkenyl, substituted or unsubstituted C1-C6 alkinyl, substituted or unsubstituted C1-C6 alkadienyl, substituted or unsubstituted C3-C6 cycloalkyl, substituted or unsubstituted C5-C10 aryl, substituted or unsubstituted C5-C10 aryloxy and combinations thereof, in particular substituted with one, two or three substituents selected from the group consisting of ethyl, methyl, propyl, isopropyl, butyl, tert.-butyl, cyclohexyl, methoxy, ethoxy, phenyloxy and combinations thereof. More specifically, R³⁹ and R⁴⁰ can be ethyl, methyl, propyl, isopropyl, butyl, tert.-butyl, cyclohexyl, phenyl, tri-ortho-tolyl, tri-meta-tolyl, tri-para-tolyl, methoxy, ethoxy, phenyloxy and combinations thereof and are different from each other.

C1-C6 alkyl means methyl (C1), ethyl (C2), propyl (C3), butyl (C4), pentyl (C5) and hexyl (C6). Propyl covers both n-propyl and iso-propyl. Butyl covers n-butyl, iso-butyl, sec-butyl and tert-butyl. Pentyl covers n-pentyl (amyl), 2-pentyl (sec-pentyl), 3-pentyl, 2-methylbutyl, 3-methylbutyl (iso-pentyl or iso-amyl), 3-methylbut-2-yl, 2-methylbut-2-yl and 2,2-dimethylpropyl (neo-pentyl). The term hexyl likewise covers all possible isomers.

Consequently, [(CpR²¹R²²R²³R²⁴R²⁵)Ru(P(R³⁸)₃)₂Cl], [(CpR²¹R²²R²³R²⁴R²⁵)Ru((R³⁹)P—R⁴⁰ ₂)₂Cl] and [(CpR²¹R²²R²³R²⁴R²⁵)Ru((R³⁹)₂P—R⁴⁰)₂Cl] can be employed as well for reacting with with R⁴R⁵(DAD)R⁶R⁷ to obtain the precursors [((CpR²¹R²²R²³R²⁴R²⁵))Ru(R⁴R⁵(DAD)R⁶R⁷)Cl], It was surprisingly found that when the reaction was carried out in the presence of pure oxygen, high yields of 70%, higher purities up to 99% or both can be achieved. The presence of oxygen can be achieved, for example, by passing a stream of pure oxygen gas, O₂, through the reaction mixture.

This surprising effect could be explained after its discovery because it was found that in this case phosphine oxide is formed and (R⁴R⁵(DAD)R⁶R⁷) becomes the stronger coordinating ligand in the reaction mixture and thus an increased yield of the desired product could be found.

Accordingly, the present invention also relates to a method for the production of a compound of formula [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³] comprising the following steps:

a) reacting [(CpR²¹R²²R²³R²⁴R²⁵)Ru(PPh₃)₂Cl] or [(CpR²¹R²²R²³R²⁴R²⁵)RuCl]₄ with R⁴R⁵(DAD)R⁶R⁷ to obtain [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)Cl],

b) reacting [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)Cl] with R³MgX or R³Li to obtain

[(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³],

wherein X is selected from the group consisting of F, Cl, Br and I.

More specifically, the present invention also relates to a method for the production of a compound of formula [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³] comprising the following steps:

a) reacting [(CpR²¹R²²R²³R²⁴R²⁵)Ru(PPh₃)₂Cl] with R⁴R⁵(DAD)R⁶R⁷ to obtain [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)Cl] in the presence of pure oxygen, b) reacting [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)Cl] with R³MgX or R³Li to obtain [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³], wherein X is selected from the group consisting of F, Cl, Br and I.

Another embodiment also relates to a method for the production of a compound of formula [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)Cl] comprising the step:

a) reacting [(CpR²¹R²²R²³R²⁴R²⁵)Ru(PPh₃)₂Cl] with R⁴R⁵(DAD)R⁶R⁷ to obtain [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)Cl] in the presence of pure oxygen, wherein X is selected from the group consisting of F, Cl, Br and I. In particular, the presence of pure oxygen means that a stream of pure oxygen (O₂) gas is passed through the reaction mixture.

In an aspect of the present invention, step a) and/or step b) is/are carried out in a solvent. In general, aromatic solvents and ethers are suitable solvents. In particular, aromatic compounds having 6 to 15 carbon atoms are suitable solvents and can be substituted or unsubstituted compounds, such as benzene, toluene, ortho- meta- or para-xylene, mesitylen, ethylbenzene, 1,2-, 1,3-, or 1,4-diethylbenzene ore triethylbenzene can be employed as solvents. In particular, linear or cyclic ethers with two to 20 carbon atoms can be used, such as dimethyl ether, ethylmethyl ether, diethyl ether, ethyl-tert.-butylether, 2-Methoxy-2-methylpropane, tetrahydropyrane, dioxane, tetrahydrofuran, glyme ordiglyme. Usually, good results can be achieved with toluene or tetrahydrofurane. It is known to the person of normal skill in the art that lithium organic compounds can, under certain conditions, react with aromatic solvents, see Wiklund, T., Olsson, S. & Lennartson, A. Monatsh Chem (2011) 142: 813. The artisan thus would, in order to avoid side reactions, check the suitability of the solvents for the specific reactions and might rather elect linear or cyclic ethers over aromatic solvents when employing lithium organic compounds such as R³Li.

In another aspect of the present invention, step a) and/or step b) can in general be carried out at a temperature of from about −78° C. to about 40° C., or from about −30° C. to about 30° C., or from about 0° C. to about 25° C. Good results were obtained by starting the reaction at a temperature of 0° C. or less and allow the reaction mixture to warm up to ambient temperature in the course of the reaction, normally without employing a means for heat treatment.

In a further aspect of the present invention, step a) and/or step b) can in general be carried out for a period of time of 3 minutes to 12 hours, or from 10 minutes to 8 hours or from 20 minutes to 6 hours or from 30 minutes to 3 hours. Good results have been achieved by reaction times of about 3 hours or less.

By varying the substitution patterns on the ligands, the thermal properties of the compound class [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³] can also be adapted, depending on the application. As an example in this respect, the two compounds [(CpMe)Ru(^(iPr)DAD)Me] and [(Cp*)Ru(^(iPr)DAD)Me] are mentioned. In the Ligand (^(iPr)DAD), R⁴ and R⁷ are Isopropyl, R⁵ and R⁶ are H.

While [(Cp*)Ru(^(iPr)DAD)Me] has a melting point of 53° C., [(CpMe)Ru(^(iPr)DAD)Me] is liquid at room temperature.

As a result of the low molar masses (e.g., for [(CpMe)Ru(^(iPr)DAD)Me] M=335.46 g/mol) in connection with being present as a single molecule, the new compounds are highly volatile compounds, which can be excellently purified by sublimation or distillation.

The compound according to the invention [(MeCp)Ru(^(iPr)DAD)Me] exhibits a narrow, single-stage decomposition curve when the compound is heated to 600° C. In the process, the 3% degradation already appears at 163.26° C. A 50% degradation of the compound appears at 194° C., with a total mass loss of 98.93% at 600° C.

By reacting the known precursor [(CpMe)Ru(PPh₃)₂Cl] with bis(isopropylimine)glyoxal under oxidative conditions (O₂) in boiling toluene, the precursor [(CpMe)Ru(^(iPr)DAD)Cl] can be obtained at an 84% yield. As a result of the following conversion with MeMgBr solution at 0° C. up to room temperature, the target compound [(CpMe)Ru(^(iPr)DAD)Me] can be obtained at a yield of 73%. The total yield of the synthesis route is, at 61%, very good. By means of distillation, the compound [(MeCp)Ru(^(iPr)DAD)Me] can, moreover, be purified easily on a large scale.

[(MeCp)Ru(^(iPr) DAD)Me] already exhibits a high vapor pressor at 70° C. at a pressure of 10⁻³ mbar. The compound [(MeCp)Ru(^(iPr)DAD)Me] exhibits a narrow, single-stage decomposition curve when the compound is heated to 600° C. In the process, the 3% degradation already appears at 163.26° C. A 50% degradation of the compound appears at 194° C., with a total mass loss of 98.93% at 600° C.

Accordingly, the present invention also relates to the use of a compound of formula [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³] to deposit elemental ruthenium or ruthenium containing layers on a surface.

In an aspect of the present invention, deposition is accomplished by means of a thermally-induced decomposition

In a further aspect of the present invention, deposition is achieved within an ALD (Atomic Layer Deposition) or a CVD (Chemical Vapor Deposition) process.

The present invention is further illustrated by the following non-limiting examples.

EXAMPLES Synthesis of [Cp*RuCl]₄ via Superhydride

(Paquette, L. A. E-EROS: Encyclopedia of reagents for organic synthesis, Online ed.; Wileylnterscience, 2010)

The synthesis of [Cp*RuCl]₄ was conducted after Kimpe, N. de; Verhé, R.; Buyck, L. de; Moens, L.; Schamp, N. Synthesis 1982, 1982 (01), 43-46. A Schlenk flask was charged with 5.10 g [Cp*RuCl₂]_(n) (16.58 mmol, 1 eq) and 30 mL THF (abs.). Then 16.6 mL LiHBEt₃ solution (1 M in THF, 16.6 mmol, 1.01 eq) was slowly added. While adding a gas evolution could be observed. The solution turns dark brown and an orange precipitate is formed. The solid was filtered and rinsed with small amounts of THF. After drying in vacuum the product was obtained as brown-orange solid 3.56 g (76%).

Synthesis of [Cp*RuCl]₄ Via Two-Step Synthesis

(Koelle, U.; Kossakowski, J. J. Chem. Soc., Chem. Commun. 1988, No. 8, 549)

[Cp*RuCl]₄ was synthesized according to Bellassoued, M.; Aatar, J.; Bouzid, M.; Damak, M. Phosphorus, Sulfur, and Silicon and the Related Elements 2010, 185 (9), 1886-1895. A flask was charged under argon with 18.0 g of K₂CO₃ (exc.) and 100 mL MeOH (abs.). 4.0 g of [Cp*RuCl₂]_(n) (13.02 mmol) were added. The colorless suspension turns dark red immediately. The solution was stirred at ambient temperature for 12 h and the red solution was filtered of the K₂CO₃ and the filter pad was thoroughly washed with pentane. The solution was evaporated to one third of the volume and a small excess of TMSCl was slowly added. The solution turns brown slowly. After staying for 2 days at 30° C. an orange precipitate forms, which was filtered off and rinsed with small amounts of pentane. The product could be obtained as orange-brown solid in quantitative yield.

Synthesis of [(MeCp)Ru(^(iPr)DAD)Cl]

[(MeCp)RuCl(^(iPr)DAD)] was prepared by an improved synthesis based on Zoet, R.; van Koten, G.; van der Panne, Albertus L. J.; Versloot, P.; Vrieze, K.; Stam, C. H. Inorganica Chimica Acta 1988, 149 (2), 177-185.

[(MeCp)RuCl(PPh₃)₂] (1.66 g, 2.24 mmol, 1 Aq.) and iPrDAD (1.57 g, 11.21 mmol, 5 Aq.) were dissolved in 200 mL of toluene and heated for 2 hours under reflux while a gentle stream of oxygen (O₂) was passed through the reaction mixture. In the course of the reaction the color changed from orange-red to bright red. The solvent was removed in vacuo and the solid dissolved in dichloro methane. This solution was purified by column chromatography (hexane/diethyl ether 4:1). The first fraction mainly contained the starting material [(MeCp)RuCl(PPh₃)₂] and was discarded. The second fraction contained the product. The solvent was removed and the product [(MeCp)Ru(iPrDAD)Cl] was obtained as a viscous oil of dark red color. Yield: 71%, Purity: >99%.

¹H-NMR (CDCl₃, 300 MHz, 300 K): δ=8.43 (s, 2H), 4.59 (dt, 2H), 4.30 (d, 4H), 1.88 (s, 3H), 1.54 (t, 12H).

Synthesis of [(Cp*)Ru(^(iPr)DAD)Cl]

was conducted according to Mbaye, M. D.; Demerseman, B.; Renaud, J.-L.; Bruneau, C. Journal of Organometallic Chemistry 2005, 690 (8), 2149-2158.

Synthesis of [(MeCp)Ru(^(iPr)DAD)Me]

A flask was charged with 10.56 mL of a [(MeCp)Ru(^(iPr)DAD)Cl] solution (0.079 M in THF (abs.), 0.84 mmol, 1 eq). At 0° C. 0.28 mL of a MeMgBr solution (3 M in Et₂O (abs.), 0.84 mmol, 1 eq) was added slowly. The reaction mixture was warmed to rt for 20 min, whereas the solution changes color from deep red-brown to neon yellow-dark brown. After further 1 h of stirring at rt, the solvent was evaporated and the residue extracted with a solvent mixture of toluene (abs.)/pentane (abs.) 1:9. The combined extracts were evaporated to dryness and the residue was extracted with pentane (abs.). After evaporation of the solvent, the product was obtained as dark brown liquid with neon yellow luster (219 mg, 73%).

¹H-NMR (C₆D₆, 300 MHz, 300 K): δ (ppm)=7.76 (s, 2H), 4.70 (t, J=1.8 Hz, 2H), 4.25 (s, 1H), 4.19 (quint, J=13.2, 6.6 Hz, 1H), 1.69 (s, 3H), 1.29 (dd, J=6.6, 3.4 Hz, 13H), 0.07 (s, 3H).

¹³C-NMR (C₆D₆, 75 MHz, 300 K): δ (ppm)=142.20 (C), 100.24 (C_(q)), 80.50 (E), 78.16 (D), 66.12 (B), 25.01 (s, A), 24.76 (s, A) 13.16 (Me_(Cp)), 9.05 (Me).

EI+/HRMS m/z (%)=336.11291 ([M]+, calc. 336.11435).

CHN C₁₅H₂₆N₂Ru: calc. N, 8.35, C, 53.71, H, 7.81; found N, 11.45, C, 53.63, H, 7.57.

TGA (10 Kmin⁻¹; T_(max)=600° C.): 3%-deg.=163.26° C.; Onset=194.79° C.

Synthesis of [(Cp*)Ru(^(iPr)DAD)Me]

A flask was charged with 300 mg [(Cp*)Ru(^(iPr)DAD)Cl] (0.75 mmol, 1 eq) and added 10 mL of toluene (abs.). At 0° C. 0.243 mL of a MeMgBr solution (3 M in Et₂O (abs.), 0.75 mmol, 1 eq) was added slowly. The reaction mixture was warmed to rt for 20 min, whereas the solution changes color from deep red-brown to neon yellow-dark brown. After further 3 h of stirring at rt, the reaction mixture was filtered and the solvent of the filtrate evaporated. The residue was extracted with pentane (abs.) and solvent of the combined extracts was evaporated. The product was obtained as dark brown oil with neon yellow luster, which solidifies after longer standing. (268 mg, 68%).

Melting point: T_(m)=53° C.

¹H-NMR (C₆D₆, 300 MHz, 300 K): δ (ppm)=7.80 (s, 2H), 4.37 (quint, J=13.5, 6.7 Hz, 2H), 1.69 (s, 15H), 1.33 (d, J=6.8 Hz, 6H), 1.30 (d, J=6.7 Hz, 6H), −0.14 (s, 3H).

¹³C-NMR (C₆D₆, 75 MHz, 300 K): δ (ppm)=138.92 (s), 89.54 (s), 62.10 (s), 24.09 (s), 23.30 (s), 13.22 (s), 10.11 (s).

EI+/HRMS m/z (%)=392.17791 ([M]+, calc. 392.17706).

CHN C₁₉H₃₄N₂Ru: calc. N, 7.15, C, 58.28, H, 8.75; found N, 7.49, C, 57.86, H, 8.30.

TGA (10 Kmin⁻¹; T_(max)=600° C.): 3%-deg.=192.59° C.; Onset=209.23° C.

The syntheses conducted for the compounds of the present invention are readily reproducible. The starting materials of these compounds are available via literature known and well established routes.

The compounds of the present invention exhibit formidable thermal properties regarding ALD processing. The thermal decomposition points are located around 200° C. In case of [(MeCp)Ru(^(iRr)DAD)Me] a one-step and for [(Cp*)Ru(^(iRr)DAD)Me] a two-step decomposition can be found. According to the mass spectra the fragments with the highest abundance are either [(Cp)Ru(DAD)] or [(Cp)Ru] fragments. Especially the fragment [(Cp)Ru] should exhibit a high volatility and thermal stability, which makes it an optimal reactive species in ALD. In a thermal measurement from 25-600° C. 98% [(MeCp)Ru(DAD)Me] and 81% [(Cp*)Ru(DAD)Me] are decomposed or evaporated. 

1. Compound of the general formula

that can also be represented by the general formula [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³], wherein R³ can be selected from the group consisting of H, C1-C6 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl, C3-C6 vinyl, C3-C6 allyl, C3-C6 alkenyl; (R⁴R⁵(DAD)R⁶R⁷) represents a chelating 1,4-diazadiene or its bis-hydrazone derivative of the general formula (R⁴)—N═CR⁵—CR⁶═N—(R⁷) wherein R⁴ and R⁷, can be independently selected from the group consisting of C1-C6 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl; or R⁴ can be (R⁸,R⁹)N— and R⁷ can be (R¹²,R¹³)N—, and R⁸, R⁹, R¹² and R¹³ can be independently selected from the group consisting of H, C1-C6 linear alkyl, C3-C6 branched alkyl, or two neighbouring groups, such as R⁸ and R⁹ or R¹² and R¹³, do together form a C3-C6 saturated or unsaturated cyclic alkyl, which may contain a heteroatom selected from O or S; R⁵ and R⁶ can be independently selected from the group consisting of H, C1-C6 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl; R²¹, R²², R²³, R²⁴ and R²⁵ are, independently from each other, selected from the group consisting of H, C1-C6 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl and NR³¹ ₂, wherein R³¹ is selected from the group consisting of H, C1-C6 linear alkyl, C3-C8 branched alkyl, C3-C6 cyclic alkyl and C3-C6 aryl; or two of R²¹, R²², R²³, R²⁴ and R²⁵ are interconnected by a C3 to C6 alkyl, alkenyl, alkadienyl or alkatrienyl forming an annelated ring that can be substituted or unsubstituted.
 2. A compound according to claim 1, wherein R³ can be selected from the group consisting of H, C1-C3 linear alkyl, C3-C5 branched alkyl; (R⁴R⁵(DAD)R⁶R⁷) represents a chelating 1,4-diazadiene or its bis-hydrazone derivative of the general formula (R⁴)—N═CR⁵—CR⁶═N—(R⁷) wherein R⁴ and R⁷, can be independently selected from the group consisting of C1-C3 linear alkyl, C3-C5 branched alkyl, C3-C6 cyclic alkyl; or R⁴ can be (R⁸,R⁹)N— and R⁷ can be (R¹²,R¹³)N—, and R⁸, R⁹, R¹² and R¹³ can be independently selected from the group consisting of H, C1-C3 linear alkyl, C3-C5 branched alkyl, or two neighbouring groups, such as R⁸ and R⁹ or R¹² and R¹³, do together form a C4 to C6 saturated or unsaturated cyclic alkyl, which may contain a heteroatom selected from O or S; R⁵ and R⁶ can be independently selected from the group consisting of H, C1-C3 linear alkyl, C3-C5 branched alkyl, C3-C6 cyclic alkyl; R²¹, R²², R²³, R²⁴ and R²⁵ are, independently from each other, selected from the group consisting of H, C1-C3 linear alkyl, C3-C6 branched alkyl, C3-C6 cyclic alkyl and NR³¹ ₂, wherein R³¹ is selected from the group consisting of H, methyl, ethyl, isopropyl; or two of R²¹, R²², R²³, R²⁴ and R²⁵ are so linked to each other as to form a phenylene which can be substituted or unsubstituted, in sum resulting in (CpR²¹R²²R²³R²⁴R²⁵) being an indenyl ligand that can be substituted or unsubstituted.
 3. A compound according to claim 1, wherein (R⁴R⁵(DAD)R⁶R⁷) represents a chelating 1,4-diazadiene derivative of the general formula (R⁴)—N═CR⁵—CR⁶═N—(R⁷) wherein R⁴ and R⁷, can be independently selected from the group consisting of C1-C3 linear alkyl, C3-C5 branched alkyl; R⁵ and R⁶ can be independently selected from the group consisting of H, C1-C3 linear alkyl, C3-C5 branched alkyl; R²¹, R²², R²³, R²⁴ and R²⁵ are, independently from each other, selected from the group consisting of H, C1-C3 linear alkyl, C3-C6 branched alkyl.
 4. A compound of claim 1, wherein R²¹, R²², R²³, R²⁴ and R²⁵ are, independently from each other, selected from the group consisting of H, methyl, ethyl, isopropyl and tert.-butyl.
 5. A compound of claim 1, wherein R²¹ to R²⁵ are not identical; or at least one of R²¹ to R²⁵ is different.
 6. A compound of claim 1, wherein R²¹ to R²⁵ are identical.
 7. A compound of claim 1, wherein R⁴ and R⁷ are, independently from each other, selected from the group consisting of methyl, ethyl, isopropyl and tert.-butyl.
 8. A compound of claim 1, wherein R⁵ and R⁶ are, independently from each other, selected from the group consisting of H, methyl, ethyl, isopropyl and tert.-butyl.
 9. A compound of claim 1, wherein R⁴ to R⁷ are not identical, or at least one of R⁴ to R⁷ is different.
 10. A compound of claim 1, wherein R⁴ and R⁷ are identical.
 11. A compound of claim 1, wherein R⁸, R⁹, R¹² and R¹³ can be, independently from each other, selected from the group consisting of C1-C3 linear alkyl, C3-C5 branched alkyl or two neighbouring groups, such as R⁸ and R⁹ or R¹² and R¹³ together forming a C4 to C8 saturated cyclic alkyl, which may contain a heteroatom selected from O or S.
 12. A compound of claim 1, wherein R⁸, R⁹, R¹² and R¹³ can be, independently from each other, selected from the group consisting of methyl, ethyl, isopropyl, tert.-butyl, pyrrolidinyl, piperidinyl or morpholinyl.
 13. A compound of claim 1, wherein (R⁴R⁵(DAD)R⁶R⁷) being selected from the group consisting of (R⁸,R⁹)N—N═CR⁵—CR⁶═N—N(R¹²,R¹³), R⁴—N═CR⁵—CR⁶═N—N(R¹²,R¹³) with R⁴ being different from (R⁸,R⁹)N, (R⁸,R⁹)N—N═CR⁵—CR⁶═N—R⁷ with R⁷ being different from (R¹²,R¹³)N, R⁴—N═CR⁵—CR⁶═N—R⁷ with R⁴ being different from (R⁸,R⁹)N and R⁷ being different from (R¹²,R¹³)N and combinations thereof.
 14. A compound of claim 1, wherein R³ is selected from the group consisting of H, methyl, ethyl and combinations thereof.
 15. A compound of claim 1, wherein the (CpR²¹R²²R²³R²⁴R²⁵) is selected from the group consisting of an unsubstituted cyclopentadienide ligand, Cp, (wherein in the formula (CpR²¹R²²R²³R²⁴R²⁵) all substituents R²¹ to R²⁵ are hydrogen), a monomethyl substituted cyclopentadienide ligand CpMe, a pentamethyl substituted cyclopentadienide ligand Cp*, a monoethyl substituted cyclopentadienide ligand EtCp and combinations thereof.
 16. Method for the production of a compound according to claim 1 comprising the following steps: a) reacting [(CpR²¹R²²R²³R²⁴R²⁵)Ru(P(R³⁸)₃)₂X], [(CpR²¹R²²R²³R²⁴R²⁵)Ru((R³⁹)P—R⁴⁰ ₂)₂X], [(CpR²¹R²²R²³R²⁴R²⁵)Ru((R³⁹)₂P—R⁴⁰)₂X] or [(CpR²¹R²²R²³R²⁴R²⁵)RuX]₄ with R⁴R⁵(DAD)R⁶R⁷ to obtain [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)X], b) reacting [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)X] with R³MgX or R³Li to obtain [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)R³], wherein R³³ and R⁴⁰ are different from each other and wherein R³⁸, R³⁹ and R⁴⁰ are selected from the group consisting of substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkyloxy, substituted or unsubstituted C1-C8 alkenyl, substituted or unsubstituted C1-C6 alkinyl, substituted or unsubstituted C1-C6 alkadienyl, substituted or unsubstituted C3-C6 cycloalkyl, substituted or unsubstituted C5-C10 aryl, substituted or unsubstituted C5-C10 aryloxy and combinations thereof, in particular substituted with one, two or three substituents selected from the group consisting of ethyl, methyl, propyl, isopropyl, butyl, tert.-butyl, and combinations thereof, and wherein specifically can be ethyl, methyl, propyl, isopropyl, butyl, tert.-butyl, cyclohexyl, phenyl, tri-ortho-tolyl, tri-meta-tolyl, tri-para-tolyl, methoxy, ethoxy, phenyloxy and combinations thereof, and X is selected from the group consisting of F, Cl, Br and I.
 17. Method according to claim 18, wherein step a) is carried out in the presence of pure oxygen and at least one of [(CpR²¹R²²R²³R²⁴R²⁵)Ru(P(R³⁸)₃)₂X], [(CpR²¹R²²R²³R²⁴R²⁵)Ru((R^(3S))P—R⁴⁰ ₂)₂X] and [(CpR²¹R²²R²³R²⁴R²⁵)Ru((R³³)₂P—R⁴⁰)₂X] Is employed.
 18. Method for the production of a compound of formula [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)X] comprising the step: a) reacting at least one of [(CpR²¹R²²R²³R²⁴R²⁵)Ru(P(R³⁸)₃)₂X], [(CpR²¹R²²R²³R²⁴R²⁵)Ru((R³³)P—R⁴⁰ ₂)₂X] and [(CpR²¹R²²R²³R²⁴R²⁵)Ru((R³⁹)₂P—R⁴⁰)₂X] with R⁴R⁵(DAD)R⁶R⁷ to obtain [(CpR²¹R²²R²³R²⁴R²⁵)Ru(R⁴R⁵(DAD)R⁶R⁷)X] in the presence of pure oxygen, wherein X is selected from the group consisting of F, Cl, Br and I and wherein R³⁹ and R⁴⁰ are different from each other and wherein R³⁸, R³⁹ and R⁴⁰ are selected from the group consisting of substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkyloxy, substituted or unsubstituted C1-C6 alkenyl, substituted or unsubstituted C1-C6 alkinyl, substituted or unsubstituted C1-C6 alkadienyl, substituted or unsubstituted C3-C6 cycloalkyl, substituted or unsubstituted C5-C10 aryl, substituted or unsubstituted C5-C10 aryloxy and combinations thereof, in particular substituted with one, two or three substituents selected from the group consisting of ethyl, methyl, propyl, isopropyl, butyl, tert-butyl, and combinations thereof, and wherein specifically can be ethyl, methyl, propyl, isopropyl, butyl, tert.-butyl, cyclohexyl, phenyl, tri-ortho-tolyl, tri-mete-tolyl, tri-para-tolyl, methoxy, ethoxy, phenyloxy and combinations thereof.
 19. Method according to claim 18, wherein the presence of pure oxygen means that a stream of pure oxygen (O₂) gas is passed through the reaction mixture.
 20. Method according to claim 16, wherein step a and/or b is carried out in the presence of a solvent selected from the group consisting of aromatic solvents and ethers.
 21. Method according to claim 20, wherein step a) and/or step b) is/are carried out in either toluene or tetrahydrofurane.
 22. Method according to claim 16, wherein step a) and/or step b) is/are carried out at a temperature of about −78° C. to about 40° C.
 23. Method according to claim 16, wherein step a) and/or step b) is/are started at a temperature of 0° C. or less and the reaction mixture is then allowed to warm up to ambient temperature in the course of the reaction.
 24. Method according to claim 16, wherein step a) and/or step b) is/are carried out for a period of time of 3 minutes to 12 hours.
 25. Method comprising utilizing the compound according to claim 1 to deposit elemental ruthenium layers or ruthenium-containing layers on a surface.
 26. Method according to claim 25, wherein deposition is accomplished by means of a thermally-induced decomposition.
 27. Method according to claim 25, wherein deposition is achieved within an ALD (Atomic Layer Deposition) or a CVD (Chemical Vapour Deposition) process.
 28. Method for depositing elemental ruthenium layers or ruthenium-containing layers on a surface comprising the steps of providing a compound of claim 1; subjecting said compound to a method to deposit elemental ruthenium layers or ruthenium-containing layers on a surface.
 29. Method of claim 28, wherein deposition is accomplished by means of a thermally-induced decomposition.
 30. Method of claim 28, wherein the method to deposit elemental ruthenium layers or ruthenium-containing layers on a surface is an ALD (Atomic Layer Deposition) or a CVD (Chemical Vapour Deposition) process. 